It is well known that sudden vascular obstructions, especially those causing heart attacks and strokes, can be prevented in many cases by regular oral doses of acetylsalicylic acid (ASA), commonly called aspirin. Unfortunately, ASA has serious side effects. It can be very irritating to the gastrointestinal tract, causing bleeding and ulceration. It can also lead to uncontrolled bleeding leading to hemorrhagic stroke. It has been shown that very small doses, such as 80 mg. every other day, can significantly reduce the incidence of cardiovascular occlusion. This regimen is not used as much as it should be used for several reasons. Many physicians are reluctant to prescribe the prophylactic use of ASA because of these side effects and also their potential liability. It is common to say, xe2x80x9cdo not take it if you are allergic to aspirinxe2x80x9d. Patients who have had discomfort after regular analgesic doses (650 mg.) are reluctant to use it. Also compliance with something that is to be taken every other day is hard to achieve.
Some features of ASA that may be useful we can infer from experience with the drug relative to heart attacks: 1) It is absorbed rapidly enough that it is effective in some cases if taken at the first sign of a heart attack. 2) Enough remains the second day after an 80 mg. dose to be effective in reducing heart attacks.
It would be useful to provide a form of aspirin that would have the maximum prophylactic value with minimal total dose. This would greatly reduce the side effects so that the benefits of the drug would be available to many more individuals. It would also be useful to find a form of the drug that would be easy to use to ensure compliance.
It is accordingly an object of the invention to provide a method and medicament formulation that will prevent vascular obstructions that lead to heart attacks and strokes with minimal side effects. The medicament is aspirin (ASA) or its derivatives. It is prepared in oral dose form to be taken at a convenient time in the evening, such as with the evening meal, or at bedtime. It is to be taken daily rather than on alternate days to enhance compliance. The dose is so prepared that, after ingestion, there will be no release of the drug into the gut in absorbable form for a preset time interval. The purpose is to ensure that the drug will reach an optimal blood level in the early morning when it is most needed. It is well known that the incidence of heart attacks is greatest in the morning. If the attack occurs at this time, the precipitating events occur somewhat earlier. By arranging to reach an optimal blood level of ASA to approximately coincide with the time when the need for the drug is greatest, the amount of drug administered can be greatly reduced. If 80 mg. is effective on the second day after administration when the blood level is very low, then a very low dose, such as 8 mg. or 16 mg., may be effective with this new formulation. Such a low dose would be easily tolerated with very low incidence of side effects.
These and other objects, features, and advantages of the invention will become more apparent when the detailed description is studied.